Explanation:
At 25 °C Dissociation constant of water or Kw = 1× 10^-14 mol2dm-6
Ka × Kb = Kw for all diluted solutions
Ka×Kb = 1 × 10^-14 mol2dm-6
Therefore for question 1 -
COOH- is the conjugate base for HCOOH ( we find the conjugate base by removing an H atom and the Conjugate acid by adding an H atom)
COOH- (aq) + H2O ( l) <-----> HCOOH( aq) + OH-(aq)
So we can apply the above mentioned equation to find Kb value for COOH-
Kb = 5.56 × 10^-11 moldm-3
For question 2-
We can see that (CH3)2NH+2 is the conjugate acid of (CH3)2 NH. (A H atom has been removed so the one with a H atom less is the conjugate base.)
(CH3)2NH+2 (aq) + H2O (l) <-----> (CH3)2 NH (aq) + H3O+ (aq)
So applying the previously mentioned equation we get Ka = 1.85 × 10^-11 moldm-3
WILL GIVE BRAINLEST
Water waves in a small tank are 6.0 cm long. They pass at a given point at a rate of 4.8 waves per second. What is the speed of the wave?
Answer:, Correct option is 0.288m/s
Explanation:
The relationship between the velocity of the wave, its wavelength and frequency is given by the formula
Wavelengthλ=
Frequency(ν)
Speed(v)
,
where, v - velocity of the wave
λ - wavelength of the wave
f - frequency of the wave.
In the question it is given that the frequency is 4.8 Hz and the wavelength is 6.0 cm, that is, 0.06 meters.
The velocity of the sound is calculated as follows.
v=f×λ=4.8 Hz×0.06 m=0.288 m/s
Hence, the speed of the water wave is 0.288 m/s.
Pick the word which best completes the sentence.
The weather man told our class that the ____ flows from west to east.
a.
air mass
c.
clouds
b.
jet stream
d.
cold front
Please select the best answer from the choices provided
A
B
C
D
Answer:
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
cc
c
c
c
c
c
c
c
c
c
ccc
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
cc
c
c
c
AMOUNG US AND THE ANSWER IS C
Explanation:
Answer:
its c
Explanation:
Why are sound waves considered a type of mechanical energy?
Question 6 options:
Sound waves can travel through space
Sound waves can travel through a solid
Sound waves transfer energy by the motion of particles
Sounds waves are made by machines
-Sound waves transfer energy by the motion of particles.
Explanation:
These particle-to-particle, mechanical vibrations of sound conductance qualify sound waves as mechanical waves. Sound energy, or energy associated with the vibrations created by a vibrating source, requires a medium to travel, which makes sound energy a mechanical wave.
Sound waves transfer energy by the motion of particles considered a type of mechanical energy.
What is mechanical energy ?Potential energy plus kinetic energy are combined to form mechanical energy. According to the concept of mechanical energy conservation, mechanical energy remains constant in an isolated system that is solely exposed to conservative forces.
The quantity of energy that a force transfers is known as mechanical work. It is a scalar quantity with joules as its SI unit, much as energy.
Since there are only microscopic forces generated by atomic collisions and no macroscopically quantifiable force, heat conduction is not regarded as a kind of work.
Transverse, longitudinal, and surface waves are the three different forms of mechanical waves. When the wave's energy goes through them, they behave differently in terms of how the medium's particles move.
Thus, option C is correct.
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HELP ME OUT PLEASE!!!!!!!!
A chemical reaction in which calcium carbonate (CaCO3) is decomposed (broken down) results in the production of two simpler compounds. (See diagram) What mass of Calcium Carbonate (CaCO3) to the nearest hundredth of a gram, is broken down in this reaction?
A) 28 00g
B) 21979
C) 49.979
D) 50.000
Answer:
49.979
Explanation:
pls help see attached pic for the question.
Answer: Evaporation and sublimation.
Explanation: Evaporation is the process of changing from liquid to gas, and sublimation is the process of changing from solid to gas.
in a certain reaction, Fe and O2 combine to form iron (iii) oxide. 14.7 moles of Fe and 13.0 moles of O2 are placed in a container and the reaction proceeds iwth 100% yield. which is the excess reactant
Answer:
Fe is the excess reactant
Reaction yields are the amount of the reactant and the products of a chemical reaction. In the reaction between iron and oxygen, iron is the excess agent.
What is excess reactant?The reactant present in an extra quantity than the other reactant in a chemical reaction which reacts with the limiting reactant is called an excess reactant.
In a reaction mixture, the excess reactant is present even when the limiting agent is completely consumed.
The chemical reaction between iron and oxygen is shown as,
[tex]\rm 4 Fe(s) + 3 O_{2}(g) \rightarrow 2 Fe_{2}O_{3}[/tex]
From the reaction, it can be said that oxygen is a limiting reagent that limits the formation of iron (iii) oxide.
Therefore, iron is an excess reactant.
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In the following reaction, what is the quantity of heat (in kJ) released when 5.87 moles of CH₄ are burned?
CH₄ (g) + 2 O₂ (g) → CO₂ (g) + 2 H₂O(g) ∆H° = -802 kJ/mol
Taking into account the definition of enthalpy of a chemical reaction, the quantity of heat released when 5.87 moles of CH₄ are burned is 4,707.74 kJ.
The enthalpy of a chemical reaction as the heat absorbed or released in a chemical reaction when it occurs at constant pressure. That is, the heat of reaction is the energy that is released or absorbed when chemicals are transformed into a chemical reaction.
The enthalpy is an extensive property, that is, it depends on the amount of matter present.
In this case, the balanced reaction is:
CH₄ (g) + 2 O₂ (g) → CO₂ (g) + 2 H₂O(g)
and the enthalpy reaction ∆H° has a value of -802 kJ/mol.
This equation indicates that when 1 mole of CH₄ reacts with 2 moles of O2, 802 kJ of heat is released.
When 5.87 moles of CH₄ are burned, then you can apply the following rule of three: if 1 mole of CH₄ releases 802 kJ of heat, 5.87 moles of CH₄ releases how much heat?
[tex]heat=\frac{5.87 molesof CH_{4}x802 kJ}{1 mol of CH_{4} }[/tex]
heat= 4,707.74 kJ
Finally, the quantity of heat released when 5.87 moles of CH₄ are burned is 4,707.74 kJ.
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https://brainly.com/question/15355361?referrer=searchResultshttps://brainly.com/question/16982510?referrer=searchResultshttps://brainly.com/question/13813185?referrer=searchResultshttps://brainly.com/question/19521752Given the ionic formula below, what is the charge on ion X? Be sure to
include the sign (+ or -). Li2 x
Answer:Charge on X = (+ 2)
Explanation:
Charge on one Cl = -1
So Charge on two Cl = -2
The molecule = Neutral = 0 charge
So, to make total charge = 0 , the X should have +2 charge
XCl2 = +2 -2 = 0
X = +2
Alkaline earth metals(Be , Mg , Ca , Sr) form such type of compounds
Explanation:
Which of the following best describes the scientific exploration of the atom?
PLS HELP= BRAINLIEST AND POINTS
Question 11 pts
What is the term for the "invisible force" that holds you to Earth's surface?
Group of answer choices
gravity
mass
attraction
matter
Flag question: Question 2
Question 21 pts
Once an object is in motion, what type of energy is being used?
Group of answer choices
kinetic energy
gravity
potential energy
Flag question: Question 3
Question 31 pts
The Moon's mass is lower than that of Earth, thus its gravity is ____ Earth’s gravity.
Group of answer choices
less than
more than
the same as
Flag question: Question 4
Question 41 pts
When you roll a ball across a rug, what slows it to a stop?
Group of answer choices
Friction resists the ball’s forward motion.
The rug doesn’t have enough momentum to keep the ball rolling.
The rug doesn’t have enough force to keep the ball rolling.
The ball isn’t moving fast enough.
Flag question: Question 5
Question 51 pts
A championship swimmer swims 20 meters in 10 seconds. What is his speed?
Group of answer choices
20 m/s
2.0 m/s
0.5 m/s
200 m/s
Flag question: Question 6
Question 61 pts
Without an unbalanced force, an object will ____.
Group of answer choices
change its direction
maintain its velocity
stop moving altogether
change its speed
Flag question: Question 7
Question 71 pts
Which of the following indicates how fast something is moving?
Group of answer choices
speed
gravity
force
inertia
Flag question: Question 8
Question 81 pts
Which of Newton's laws is also known as the law of inertia?
Group of answer choices
Newton's third law
Newton's first law
Newton's second law
Flag question: Question 9
Question 91 pts
Which object would need the greatest force to overcome its inertia?
Group of answer choices
a sports car
a bicycle
a dump truck
a tennis ball
Flag question: Question 10
Question 101 pts
Which of the following is described by the change in an object’s position?
Group of answer choices
force
position
motion
Explanation:
gravity
kinetic energy
less than
friction resists the ball's movement
2.0 m/s
change its direction
speed
newton's first law
dump truck
position
Answer:
Q1 - Gravity
Q2 - Kinetic Energy
Q3 - Less than
Q4 - Friction resists the ball's forward motion
Q5 - 2 m/a
Q6 - Change its speed
Q7 - Speed
Q8 - Second law
Q9 - a dump truck
Q10 - motion
I am not sure about some answers but I answered all questions.
an expression of Avogradros law
Answer:
The formula for Avagadro's law is V1/n1 = V2/n2, where V = volume and n = amount of gas (in moles).
Explanation:
A 4.0 L flask containing N2 at 15 atm is connected to a 4.0 L flask containing H2 at 7.0 atm and the gases are allowed to mix. What is the mole fraction of N2
The mole fraction of N₂ after the mixture of 4.0 L of N₂ at 15 atm with 4.0 L of H₂ at 7.0 atm is 0.68.
We can calculate the mole fraction of N₂ with the following equation:
[tex] X_{N_{2}} = \frac{n_{N_{2}}}{n_{t}} = \frac{n_{N_{2}}}{n_{N_{2}} + n_{H_{2}}} [/tex] (1)
The number of moles of N₂ and H₂ can be found with the ideal gas law:
[tex] PV = nRT [/tex]
Where:
P: is the pressure
R: is the gas constant
T: is the temperature
V: is the volume
For nitrogen gas we have:
[tex] n_{N_{2}} = \frac{P_{N_{2}}V_{N_{2}}}{RT} [/tex] (2)
And for hydrogen:
[tex] n_{H_{2}} = \frac{P_{H_{2}}V_{H_{2}}}{RT} [/tex] (3)
After entering equations (2) and (3) into (1), we get:
[tex] X_{N_{2}} = \frac{\frac{P_{N_{2}}V_{N_{2}}}{RT}}{\frac{P_{N_{2}}V_{N_{2}}}{RT} + \frac{P_{H_{2}}V_{H_{2}}}{RT}} [/tex]
Since RT are constants, we have:
[tex] X_{N_{2}} = \frac{P_{N_{2}}V_{N_{2}}}{P_{N_{2}}V_{N_{2}} + P_{H_{2}}V_{H_{2}}} [/tex]
We know that:
[tex] P_{N_{2}} = 15 atm[/tex]
[tex] V_{N_{2}} = 4.0 L[/tex]
[tex] P_{H_{2}} = 7.0 atm[/tex]
[tex] V_{H_{2}} = 4.0 L[/tex]
so:
[tex] X_{N_{2}} = \frac{15 atm*4.0 L}{15 atm*4.0 L + 7.0 amt*4.0 L} = 0.68 [/tex]
Therefore, the mole fraction of N₂ is 0.68.
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A 0.48-mole sample of helium gas occupies a volume of 11.7 L . What is the volume of 0.72 mol of helium gas under the same conditions
AnswerExplanation:I finsished d
Answer:
17.55L
Explanation:
0.48mol : 11.7
0.72mol : x
0.48x = 8.424
x = 17.55
What is the [H+] if pOH =9.50
will it be acid or basic?
Taking into account the definition of pH and pOH, the [H⁺] is 3.16×10⁻⁵ M and the solution will be acid.
First of all, pH is a measure of acidity or alkalinity that indicates the amount of hydrogen ions present in a solution or substance.
The pH is defined as the negative base 10 logarithm of the activity of hydrogen ions, that is, the concentration of hydrogen ions or H₃O⁺:
pH= - log [H⁺]= - log [H₃O⁺]
Similarly, pOH is a measure of hydroxyl ions in a solution and is expressed as the logarithm of the concentration of OH⁻ ions, with the sign changed:
pOH= - log [OH⁻]
The following relationship can be established between pH and pOH:
pH + pOH= 14
In this case, being pOH= 9.50, pH is calculated as:
pH + 9.40= 14
pH= 14 - 9.50
pH= 4.50
Replacing in the definition of pH the concentration of H⁺ ions is obtained:
- log [H⁺]= 4.50
Solving :
[H⁺]= 10⁻⁴ ⁵
[H⁺]= 3.16×10⁻⁵ M
The numerical scale that measures the pH of the substances includes the numbers from 0 to 14, being acidic solutions with a pH lower than 7, and basic those with a pH greater than 7. The pH = 7 indicates the neutrality of the solution.
In this case, the pH has a value of 4.50. So, the solution is acidic.
In summary, the [H⁺] is 3.16×10⁻⁵ M and the solution will be acid.
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How can you increase the kinetic energy of the particles in a substance?
Answer: A rise in temperature increases the kinetic energy and speed of particles; it does not weaken the forces between them. The particles in solids vibrate about fixed positions; even at very low temperatures. Individual particles in liquids and gases have no fixed positions and move chaotically.
Answer:
energy kinetic particles in substance
How to find distance from motion graph velocity - time?
Answer:
by finding the slope of tangent (y2 - y1)/(x2 - x1)
What is the freezing point, in Celsius, of a sucrose-water solution containing 2.23g sucrose per 100g water. The molal freezing point depression constant for water is 1.86oC/m.
The freezing point of the solution is - 0.12 oC.
We know that;
ΔT = K m i
ΔT = Freezing point depression
K = Freezing constant
m = molality
i = Van't Hoff factor
Number of moles of sucrose= 2.23g/342 g/mol = 0.0065 moles
Mass of solvent in Kg = 0.1 Kg
Molality of the solution = 0.0065 moles/ 0.1 Kg = 0.065 m
Now;
ΔT = 1.86 oC/m × 0.065 m × 1
ΔT = 0.12 oC
Freezing point of pure water = 0 oC
Freezing point of solution = 0 oC - 0.12 oC = - 0.12 oC
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In this photograph, a soccer player is about to kick the ball. Use the situation to explain that when two objects interact, the force between them can cause energy to be transferred. In your response, identify the type of energy that each object has before they interact, the forces exerted when the objects interact, and the type of energy that each object has after they interact.
The explanation to the question is stated as follows:
Newton's first law of motion states that: a body will continue in its state of rest or uniform motion unless an external force acts on it. So then, the ball initially possesses potential energy because it was at rest. While the leg of the soccer player possesses kinetic energy because its in motion.
Thus, when the player hits the ball, a force known as push has been applied. This would ensure that the ball compels and moves in the direction of the applied force. Therefore after the interaction, the leg of the player now possesses potential energy, since it would come to rest after hitting the ball. While the ball would start moving, now possessing kinetic energy.
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Can you help me with these questions?
I already did 3 which are the highlighted ones. Help me with the ones that are not.
A stock solution containing Mn2 ions was prepared by dissolving 1.269 g pure manganese metal in nitric acid and diluting to a final volume of 2.000 L. The following solutions were then prepared by dilution: For solution A, 40.00 mL of stock solution was diluted to 1500.0 mL. For solution B, 10.00 mL of solution A was diluted to 250.0 mL. For solution C, 20.00 mL of solution B was diluted to 550.0 mL. a Calculate the concentration of the stock solution.
Answer:
B.
Explanation:
Hope this helpssss
<33
How many mL of 0.150 M HF solution are required to produce 0.0370 moles of HF
Answer:
247 ml
Explanation:
How many mL of 0.150 M HF solution are required to produce 0.0370 moles of HF 0.150 moles/ liter = 0.150/1000 moles/ml =0.000150 moles/ml
0.000150 x ? = 0.0370 moles HF
? = 0.0370/0.000150 = 247 ml
check
247 ml = 247/1000 L = 0.247
(0.247) x (0.150) =0.370 check
What does a chemical reaction tell us?
Answer:
A chemical reaction rearranges the constituent atoms of the reactants to create different substances as products. The properties of the products are different from those of the reactants.
I hope this helps.
Can anybody complete this for me?
Answer:
I wish i could
Explanation:
A solution that contains less than the amount of solute that would be dissolved at equilibrium is considered to be
Answer:
dilute solution
A solution containing less solute than the equilibrium amount is called a dilute solution. The solvent has a limited capacity to dissolve a solute.
Explanation:
7. What's the structure of methane, CH,? Is it polar or non-polar?
O A. Trigonal planar, polar
O B. Tetrahedral, polar
O C. Trigonal planar, non-polar
O D. Tetrahedral, non-polar
Answer:
The answer is D.
Explanation:
Methane (CH4) is a non-polar hydrocarbon molecule made of a single carbon atom and four hydrogen atoms. It is found in nature in the form of natural gas. It is non-polar because the difference in electronegativities between carbon and hydrogen is not sufficient to produce a polarized chemical connection between these two elements.
The methane molecule has a tetrahedral structure in terms of molecular geometry. Because the molecule is not planar, the angles between the H-C-H bonds are 109.5°, which is more than the 90° that they would be if the molecule were planar.
Explanation:
tetrahedral, non polar
3.00 L of a gas is collected at 35.0 C and 0.93 atm. What is the volume at STP
Which of the following does not change the rate of collisions between particles in a reaction?
A. Addition of catalyst
B. increase in surface area
C. increase in temperature
D. decrease in the reaction volume
Answer: C
Explanation: trust me bro
Increase in temperature does not change the rate of collisions between particles in a reaction.
What is Collision?The collision hypothesis offers suggestions for how to alter the rate of a reaction as well as an explanation for why certain reactions occur at various rates.
According to the collision theory, for a chemical reaction to take place, the reacting particles must come into contact with one another. The frequency of collisions affects the reaction's rate. According to the idea, responding particles frequently encounter without reacting.
Any analysis of an ordinary reaction mechanism must start with this rule. It explains why there are so few termolecular reactions. According to the kinetic theory of gases, there will only be one instance in which three molecules collide at once out of every 1000 binary collisions.
Therefore, Increase in temperature does not change the rate of collisions between particles in a reaction.
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How do we know flowing water is the geologic process that formed the channel on Mars?
Evidence that water was once present on a planet is evidence that the planet may once have had living organisms. When landforms on different rocky planets look similar, it is evidence that they may have been formed by the same geologic process. The channel on Mars may have been caused by flowing water or flowing lava.
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How could you tell if a substance has undergone a physical change or a chemical one?
Answer: Chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. These processes are called chemical reactions and, in general, are not reversible except by further chemical reactions.
A physical change is are changes affecting the form of a chemical substance, but not its chemical composition. Physical changes are used to separate mixtures into their component compounds, but can not usually be used to separate compounds into chemical elements or simpler compounds.
What would be the freezing point of a solution that has a molality of 1.506 m which was prepared by dissolving biphenyl (C12H10) into naphthalene
The freezing point of a solution prepared by dissolving biphenyl (C12H10) into naphthalene is 67.99oC.
Freezing point can be obtained from;
ΔT = K m i
ΔT = freezing point depression
m = molality of the solution = 1.506 m
i = Van't Hoff factor = 1 for molecular substances
K = Freezing constant of naphthalene = 8.15 oC/m
ΔT = 8.15 oC/m × 1.506 m × 1 = 12.27oC
Freezing point of pure naphthalene = 80.26 °C
ΔT = Freezing point of pure naphthalene - Freezing point of solution
Freezing point of solution = Freezing point of pure naphthalene - ΔT
Freezing point of solution = 80.26 °C - 12.27oC = 67.99oC
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